[mlir] Use {} instead of std::nullopt to initialize empty ArrayRef

mlir/include/mlir/AsmParser/AsmParserState.h

@@ -195,7 +195,7 @@ class AsmParserState {
   /// Finalize the most recently started operation definition.
   void finalizeOperationDefinition(
       Operation *op, SMRange nameLoc, SMLoc endLoc,
-      ArrayRef<std::pair<unsigned, SMLoc>> resultGroups = std::nullopt);
+      ArrayRef<std::pair<unsigned, SMLoc>> resultGroups = {});
 
   /// Start a definition for a region nested under the current operation.
   void startRegionDefinition();

mlir/include/mlir/CAPI/Wrap.h

@@ -44,7 +44,7 @@ static llvm::ArrayRef<CppTy> unwrapList(size_t size, CTy *first,
       "incompatible C and C++ types");
 
   if (size == 0)
-    return std::nullopt;
+    return {};
 
   assert(storage.empty() && "expected to populate storage");
   storage.reserve(size);

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

@@ -413,7 +413,7 @@ def LLVM_LoadOp : LLVM_MemAccessOpBase<"load",
     auto *inst = builder.CreateLoad($_resultType, $addr, $volatile_);
     $res = inst;
     if ($invariant) {
-      llvm::MDNode *metadata = llvm::MDNode::get(inst->getContext(), std::nullopt);
+      llvm::MDNode *metadata = llvm::MDNode::get(inst->getContext(), {});
       inst->setMetadata(llvm::LLVMContext::MD_invariant_load, metadata);
     }
   }] # setOrderingCode

mlir/include/mlir/Dialect/PDL/IR/PDLOps.td

@@ -363,7 +363,7 @@ def PDL_OperationOp : PDL_Op<"operation", [AttrSizedOperandSegments]> {
   let builders = [
     OpBuilder<(ins CArg<"std::optional<StringRef>", "std::nullopt">:$name,
       CArg<"ValueRange", "std::nullopt">:$operandValues,
-      CArg<"ArrayRef<StringRef>", "std::nullopt">:$attrNames,
+      CArg<"ArrayRef<StringRef>", "{}">:$attrNames,
       CArg<"ValueRange", "std::nullopt">:$attrValues,
       CArg<"ValueRange", "std::nullopt">:$resultTypes), [{
       auto nameAttr = name ? $_builder.getStringAttr(*name) : StringAttr();

mlir/include/mlir/ExecutionEngine/ExecutionEngine.h

@@ -157,8 +157,7 @@ class ExecutionEngine {
 
   /// Invokes the function with the given name passing it the list of opaque
   /// pointers to the actual arguments.
-  llvm::Error invokePacked(StringRef name,
-                           MutableArrayRef<void *> args = std::nullopt);
+  llvm::Error invokePacked(StringRef name, MutableArrayRef<void *> args = {});
 
   /// Trait that defines how a given type is passed to the JIT code. This
   /// defaults to passing the address but can be specialized.

mlir/include/mlir/IR/BlockSupport.h

@@ -106,7 +106,7 @@ class BlockRange final
           Block *, Block *, Block *> {
 public:
   using RangeBaseT::RangeBaseT;
-  BlockRange(ArrayRef<Block *> blocks = std::nullopt);
+  BlockRange(ArrayRef<Block *> blocks = {});
   BlockRange(SuccessorRange successors);
   template <typename Arg, typename = std::enable_if_t<std::is_constructible<
                               ArrayRef<Block *>, Arg>::value>>

mlir/include/mlir/IR/Builders.h

@@ -465,14 +465,14 @@ class OpBuilder : public Builder {
   /// should match the size of `argTypes`.
   Block *createBlock(Region *parent, Region::iterator insertPt = {},
                      TypeRange argTypes = std::nullopt,
-                     ArrayRef<Location> locs = std::nullopt);
+                     ArrayRef<Location> locs = {});
 
   /// Add new block with 'argTypes' arguments and set the insertion point to the
   /// end of it. The block is placed before 'insertBefore'. `locs` contains the
   /// locations of the inserted arguments, and should match the size of
   /// `argTypes`.
   Block *createBlock(Block *insertBefore, TypeRange argTypes = std::nullopt,
-                     ArrayRef<Location> locs = std::nullopt);
+                     ArrayRef<Location> locs = {});
 
   //===--------------------------------------------------------------------===//
   // Operation Creation

mlir/include/mlir/IR/BuiltinAttributes.td

@@ -516,7 +516,7 @@ def Builtin_DictionaryAttr : Builtin_Attr<"Dictionary", "dictionary"> {
   }];
   let parameters = (ins ArrayRefParameter<"NamedAttribute", "">:$value);
   let builders = [
-    AttrBuilder<(ins CArg<"ArrayRef<NamedAttribute>", "std::nullopt">:$value)>
+    AttrBuilder<(ins CArg<"ArrayRef<NamedAttribute>", "{}">:$value)>
   ];
   let extraClassDeclaration = [{
     using ValueType = ArrayRef<NamedAttribute>;

mlir/include/mlir/IR/BuiltinTypes.td

@@ -1114,7 +1114,7 @@ def Builtin_UnrankedMemRef : Builtin_Type<"UnrankedMemRef", "unranked_memref", [
     using ShapedType::Trait<UnrankedMemRefType>::getDimSize;
     using ShapedType::Trait<UnrankedMemRefType>::getDynamicDimIndex;
 
-    ArrayRef<int64_t> getShape() const { return std::nullopt; }
+    ArrayRef<int64_t> getShape() const { return {}; }
 
     /// [deprecated] Returns the memory space in old raw integer representation.
     /// New `Attribute getMemorySpace()` method should be used instead.
@@ -1173,7 +1173,7 @@ def Builtin_UnrankedTensor : Builtin_Type<"UnrankedTensor", "unranked_tensor", [
     using ShapedType::Trait<UnrankedTensorType>::getDimSize;
     using ShapedType::Trait<UnrankedTensorType>::getDynamicDimIndex;
 
-    ArrayRef<int64_t> getShape() const { return std::nullopt; }
+    ArrayRef<int64_t> getShape() const { return {}; }
   }];
   let skipDefaultBuilders = 1;
   let genVerifyDecl = 1;

mlir/include/mlir/IR/Matchers.h

@@ -88,7 +88,7 @@ struct constant_op_binder {
 
     // Fold the constant to an attribute.
     SmallVector<OpFoldResult, 1> foldedOp;
-    LogicalResult result = op->fold(/*operands=*/std::nullopt, foldedOp);
+    LogicalResult result = op->fold(/*operands=*/{}, foldedOp);
     (void)result;
     assert(succeeded(result) && "expected ConstantLike op to be foldable");
 

mlir/include/mlir/IR/PatternMatch.h

@@ -853,8 +853,7 @@ class RewritePatternSet {
   RewritePatternSet &add(ConstructorArg &&arg, ConstructorArgs &&...args) {
     // The following expands a call to emplace_back for each of the pattern
     // types 'Ts'.
-    (addImpl<Ts>(/*debugLabels=*/std::nullopt,
-                 std::forward<ConstructorArg>(arg),
+    (addImpl<Ts>(/*debugLabels=*/{}, std::forward<ConstructorArg>(arg),
                  std::forward<ConstructorArgs>(args)...),
      ...);
     return *this;
@@ -937,7 +936,7 @@ class RewritePatternSet {
   RewritePatternSet &insert(ConstructorArg &&arg, ConstructorArgs &&...args) {
     // The following expands a call to emplace_back for each of the pattern
     // types 'Ts'.
-    (addImpl<Ts>(/*debugLabels=*/std::nullopt, arg, args...), ...);
+    (addImpl<Ts>(/*debugLabels=*/{}, arg, args...), ...);
     return *this;
   }
 

mlir/include/mlir/IR/Region.h

@@ -353,7 +353,7 @@ class RegionRange
 public:
   using RangeBaseT::RangeBaseT;
 
-  RegionRange(MutableArrayRef<Region> regions = std::nullopt);
+  RegionRange(MutableArrayRef<Region> regions = {});
 
   template <typename Arg, typename = std::enable_if_t<std::is_constructible<
                               ArrayRef<std::unique_ptr<Region>>, Arg>::value>>

mlir/include/mlir/IR/SymbolTable.h

@@ -395,7 +395,8 @@ class SymbolUserMap {
   /// Return the users of the provided symbol operation.
   ArrayRef<Operation *> getUsers(Operation *symbol) const {
     auto it = symbolToUsers.find(symbol);
-    return it != symbolToUsers.end() ? it->second.getArrayRef() : std::nullopt;
+    return it != symbolToUsers.end() ? it->second.getArrayRef()
+                                     : ArrayRef<Operation *>();
   }
 
   /// Return true if the given symbol has no uses.

mlir/include/mlir/IR/TypeRange.h

@@ -36,7 +36,7 @@ class TypeRange : public llvm::detail::indexed_accessor_range_base<
                       Type, Type, Type> {
 public:
   using RangeBaseT::RangeBaseT;
-  TypeRange(ArrayRef<Type> types = std::nullopt);
+  TypeRange(ArrayRef<Type> types = {});
   explicit TypeRange(OperandRange values);
   explicit TypeRange(ResultRange values);
   explicit TypeRange(ValueRange values);
@@ -47,6 +47,7 @@ class TypeRange : public llvm::detail::indexed_accessor_range_base<
   template <typename Arg, typename = std::enable_if_t<std::is_constructible<
                               ArrayRef<Type>, Arg>::value>>
   TypeRange(Arg &&arg) : TypeRange(ArrayRef<Type>(std::forward<Arg>(arg))) {}
+  TypeRange(std::nullopt_t) : TypeRange(ArrayRef<Type>()) {}
   TypeRange(std::initializer_list<Type> types)
       : TypeRange(ArrayRef<Type>(types)) {}
 

mlir/include/mlir/IR/ValueRange.h

@@ -123,7 +123,7 @@ class MutableOperandRange {
   /// and range length. `operandSegments` is an optional set of operand segments
   /// to be updated when mutating the operand list.
   MutableOperandRange(Operation *owner, unsigned start, unsigned length,
-                      ArrayRef<OperandSegment> operandSegments = std::nullopt);
+                      ArrayRef<OperandSegment> operandSegments = {});
   MutableOperandRange(Operation *owner);
 
   /// Construct a new mutable range for the given OpOperand.
@@ -392,6 +392,7 @@ class ValueRange final
                 std::is_constructible<ArrayRef<Value>, Arg>::value &&
                 !std::is_convertible<Arg, Value>::value>>
   ValueRange(Arg &&arg) : ValueRange(ArrayRef<Value>(std::forward<Arg>(arg))) {}
+  ValueRange(std::nullopt_t) : ValueRange(ArrayRef<Value>()) {}
   ValueRange(const Value &value) : ValueRange(&value, /*count=*/1) {}
   ValueRange(const std::initializer_list<Value> &values)
       : ValueRange(ArrayRef<Value>(values)) {}
@@ -401,7 +402,7 @@ class ValueRange final
       : ValueRange(ResultRange(values)) {}
   ValueRange(ArrayRef<BlockArgument> values)
       : ValueRange(ArrayRef<Value>(values.data(), values.size())) {}
-  ValueRange(ArrayRef<Value> values = std::nullopt);
+  ValueRange(ArrayRef<Value> values = {});
   ValueRange(OperandRange values);
   ValueRange(ResultRange values);
 

mlir/include/mlir/Rewrite/FrozenRewritePatternSet.h

@@ -47,10 +47,9 @@ class FrozenRewritePatternSet {
   /// `RewritePatternSet::addWithLabel`. Debug names may be empty, but patterns
   /// created with `RewritePattern::create` have their default debug name set to
   /// their type name.
-  FrozenRewritePatternSet(
-      RewritePatternSet &&patterns,
-      ArrayRef<std::string> disabledPatternLabels = std::nullopt,
-      ArrayRef<std::string> enabledPatternLabels = std::nullopt);
+  FrozenRewritePatternSet(RewritePatternSet &&patterns,
+                          ArrayRef<std::string> disabledPatternLabels = {},
+                          ArrayRef<std::string> enabledPatternLabels = {});
 
   /// Return the op specific native patterns held by this list.
   const OpSpecificNativePatternListT &getOpSpecificNativePatterns() const {

mlir/include/mlir/Support/StorageUniquer.h

@@ -97,7 +97,7 @@ class StorageUniquer {
     template <typename T>
     ArrayRef<T> copyInto(ArrayRef<T> elements) {
       if (elements.empty())
-        return std::nullopt;
+        return {};
       auto result = allocator.Allocate<T>(elements.size());
       std::uninitialized_copy(elements.begin(), elements.end(), result);
       return ArrayRef<T>(result, elements.size());

mlir/include/mlir/Tools/PDLL/AST/Nodes.h

@@ -897,8 +897,8 @@ class UserConstraintDecl final
                                         ArrayRef<VariableDecl *> results,
                                         const CompoundStmt *body,
                                         Type resultType) {
-    return createImpl(ctx, name, inputs, /*nativeInputTypes=*/std::nullopt,
-                      results, /*codeBlock=*/std::nullopt, body, resultType);
+    return createImpl(ctx, name, inputs, /*nativeInputTypes=*/{}, results,
+                      /*codeBlock=*/std::nullopt, body, resultType);
   }
 
   /// Return the name of the constraint.

mlir/include/mlir/Tools/PDLL/AST/Types.h

@@ -253,8 +253,7 @@ class TupleType : public Type::TypeBase<detail::TupleTypeStorage> {
   /// Return an instance of the Tuple type.
   static TupleType get(Context &context, ArrayRef<Type> elementTypes,
                        ArrayRef<StringRef> elementNames);
-  static TupleType get(Context &context,
-                       ArrayRef<Type> elementTypes = std::nullopt);
+  static TupleType get(Context &context, ArrayRef<Type> elementTypes = {});
 
   /// Return the element types of this tuple.
   ArrayRef<Type> getElementTypes() const;

mlir/include/mlir/Transforms/Passes.h

@@ -62,8 +62,8 @@ std::unique_ptr<Pass> createCanonicalizerPass();
 /// set to their type name.
 std::unique_ptr<Pass>
 createCanonicalizerPass(const GreedyRewriteConfig &config,
-                        ArrayRef<std::string> disabledPatterns = std::nullopt,
-                        ArrayRef<std::string> enabledPatterns = std::nullopt);
+                        ArrayRef<std::string> disabledPatterns = {},
+                        ArrayRef<std::string> enabledPatterns = {});
 
 /// Creates a pass to perform control-flow sinking.
 std::unique_ptr<Pass> createControlFlowSinkPass();

mlir/lib/Conversion/PDLToPDLInterp/PDLToPDLInterp.cpp

@@ -991,7 +991,7 @@ void PDLToPDLInterpPass::runOnOperation() {
       module.getLoc(), pdl_interp::PDLInterpDialect::getMatcherFunctionName(),
       builder.getFunctionType(builder.getType<pdl::OperationType>(),
                               /*results=*/std::nullopt),
-      /*attrs=*/std::nullopt);
+      /*attrs=*/ArrayRef<NamedAttribute>());
 
   // Create a nested module to hold the functions invoked for rewriting the IR
   // after a successful match.

mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp

@@ -243,8 +243,8 @@ static Value createLinalgBodyCalculationForElementwiseOp(
     auto shifted =
         rewriter.create<arith::ShRSIOp>(loc, resultTypes, args[0], subtract)
             ->getResults();
-    auto truncated =
-        rewriter.create<arith::TruncIOp>(loc, i1Ty, shifted, std::nullopt);
+    auto truncated = rewriter.create<arith::TruncIOp>(
+        loc, i1Ty, shifted, llvm::ArrayRef<NamedAttribute>());
     auto isInputOdd =
         rewriter.create<arith::AndIOp>(loc, i1Ty, truncated, i1one);
 
@@ -447,20 +447,20 @@ static Value createLinalgBodyCalculationForElementwiseOp(
 
     if (isa<FloatType>(srcTy) && isa<FloatType>(dstTy) && bitExtend)
       return rewriter.create<arith::ExtFOp>(loc, resultTypes, args,
-                                            std::nullopt);
+                                            llvm::ArrayRef<NamedAttribute>());
 
     if (isa<FloatType>(srcTy) && isa<FloatType>(dstTy) && !bitExtend)
       return rewriter.create<arith::TruncFOp>(loc, resultTypes, args,
-                                              std::nullopt);
+                                              llvm::ArrayRef<NamedAttribute>());
 
     // 1-bit integers need to be treated as signless.
     if (srcTy.isInteger(1) && arith::UIToFPOp::areCastCompatible(srcTy, dstTy))
       return rewriter.create<arith::UIToFPOp>(loc, resultTypes, args,
-                                              std::nullopt);
+                                              llvm::ArrayRef<NamedAttribute>());
 
     if (srcTy.isInteger(1) && isa<IntegerType>(dstTy) && bitExtend)
       return rewriter.create<arith::ExtUIOp>(loc, resultTypes, args,
-                                             std::nullopt);
+                                             llvm::ArrayRef<NamedAttribute>());
 
     // Unsigned integers need an unrealized cast so that they can be passed
     // to UIToFP.
@@ -478,7 +478,7 @@ static Value createLinalgBodyCalculationForElementwiseOp(
     // All other si-to-fp conversions should be handled by SIToFP.
     if (arith::SIToFPOp::areCastCompatible(srcTy, dstTy))
       return rewriter.create<arith::SIToFPOp>(loc, resultTypes, args,
-                                              std::nullopt);
+                                              llvm::ArrayRef<NamedAttribute>());
 
     // Casting to boolean, floats need to only be checked as not-equal to zero.
     if (isa<FloatType>(srcTy) && dstTy.isInteger(1)) {
@@ -585,7 +585,7 @@ static Value createLinalgBodyCalculationForElementwiseOp(
 
     if (isa<IntegerType>(srcTy) && isa<IntegerType>(dstTy) && bitExtend)
       return rewriter.create<arith::ExtSIOp>(loc, resultTypes, args,
-                                             std::nullopt);
+                                             llvm::ArrayRef<NamedAttribute>());
 
     if (isa<IntegerType>(srcTy) && isa<IntegerType>(dstTy) && !bitExtend) {
       return rewriter.create<arith::TruncIOp>(loc, dstTy, args[0]);

mlir/lib/Dialect/Async/IR/Async.cpp

@@ -309,7 +309,7 @@ void FuncOp::build(OpBuilder &builder, OperationState &state, StringRef name,
     return;
   assert(type.getNumInputs() == argAttrs.size());
   function_interface_impl::addArgAndResultAttrs(
-      builder, state, argAttrs, /*resultAttrs=*/std::nullopt,
+      builder, state, argAttrs, /*resultAttrs=*/{},
       getArgAttrsAttrName(state.name), getResAttrsAttrName(state.name));
 }
 

mlir/lib/Dialect/EmitC/IR/EmitC.cpp

@@ -530,7 +530,7 @@ void FuncOp::build(OpBuilder &builder, OperationState &state, StringRef name,
     return;
   assert(type.getNumInputs() == argAttrs.size());
   function_interface_impl::addArgAndResultAttrs(
-      builder, state, argAttrs, /*resultAttrs=*/std::nullopt,
+      builder, state, argAttrs, /*resultAttrs=*/{},
       getArgAttrsAttrName(state.name), getResAttrsAttrName(state.name));
 }
 

mlir/lib/Dialect/Func/IR/FuncOps.cpp

@@ -191,7 +191,7 @@ void FuncOp::build(OpBuilder &builder, OperationState &state, StringRef name,
     return;
   assert(type.getNumInputs() == argAttrs.size());
   function_interface_impl::addArgAndResultAttrs(
-      builder, state, argAttrs, /*resultAttrs=*/std::nullopt,
+      builder, state, argAttrs, /*resultAttrs=*/{},
       getArgAttrsAttrName(state.name), getResAttrsAttrName(state.name));
 }
 

mlir/lib/Dialect/GPU/Transforms/DecomposeMemRefs.cpp

@@ -55,7 +55,7 @@ static bool isInsideLaunch(Operation *op) {
 static std::tuple<Value, OpFoldResult, SmallVector<OpFoldResult>>
 getFlatOffsetAndStrides(OpBuilder &rewriter, Location loc, Value source,
                         ArrayRef<OpFoldResult> subOffsets,
-                        ArrayRef<OpFoldResult> subStrides = std::nullopt) {
+                        ArrayRef<OpFoldResult> subStrides = {}) {
   auto sourceType = cast<MemRefType>(source.getType());
   auto sourceRank = static_cast<unsigned>(sourceType.getRank());
 
@@ -110,8 +110,9 @@ static Value getFlatMemref(OpBuilder &rewriter, Location loc, Value source,
   auto &&[base, offset, ignore] =
       getFlatOffsetAndStrides(rewriter, loc, source, offsetsTemp);
   MemRefType retType = inferCastResultType(base, offset);
-  return rewriter.create<memref::ReinterpretCastOp>(loc, retType, base, offset,
-                                                    std::nullopt, std::nullopt);
+  return rewriter.create<memref::ReinterpretCastOp>(
+      loc, retType, base, offset, llvm::ArrayRef<OpFoldResult>(),
+      llvm::ArrayRef<OpFoldResult>());
 }
 
 static bool needFlatten(Value val) {

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -2510,7 +2510,7 @@ void LLVMFuncOp::build(OpBuilder &builder, OperationState &result,
   assert(llvm::cast<LLVMFunctionType>(type).getNumParams() == argAttrs.size() &&
          "expected as many argument attribute lists as arguments");
   function_interface_impl::addArgAndResultAttrs(
-      builder, result, argAttrs, /*resultAttrs=*/std::nullopt,
+      builder, result, argAttrs, /*resultAttrs=*/{},
       getArgAttrsAttrName(result.name), getResAttrsAttrName(result.name));
 }
 

mlir/lib/Dialect/LLVMIR/IR/TypeDetail.h

@@ -69,7 +69,7 @@ struct LLVMStructTypeStorage : public TypeStorage {
   class Key {
   public:
     /// Constructs a key for an identified struct.
-    Key(StringRef name, bool opaque, ArrayRef<Type> types = std::nullopt)
+    Key(StringRef name, bool opaque, ArrayRef<Type> types = {})
         : types(types), name(name), identified(true), packed(false),
           opaque(opaque) {}
     /// Constructs a key for a literal struct.

mlir/lib/Dialect/Shape/IR/Shape.cpp

@@ -1290,7 +1290,7 @@ void FuncOp::build(OpBuilder &builder, OperationState &state, StringRef name,
     return;
   assert(type.getNumInputs() == argAttrs.size());
   function_interface_impl::addArgAndResultAttrs(
-      builder, state, argAttrs, /*resultAttrs=*/std::nullopt,
+      builder, state, argAttrs, /*resultAttrs=*/{},
       getArgAttrsAttrName(state.name), getResAttrsAttrName(state.name));
 }
 

mlir/lib/IR/Diagnostics.cpp

@@ -710,7 +710,7 @@ SourceMgrDiagnosticVerifierHandlerImpl::computeExpectedDiags(
     raw_ostream &os, llvm::SourceMgr &mgr, const llvm::MemoryBuffer *buf) {
   // If the buffer is invalid, return an empty list.
   if (!buf)
-    return std::nullopt;
+    return {};
   auto &expectedDiags = expectedDiagsPerFile[buf->getBufferIdentifier()];
 
   // The number of the last line that did not correlate to a designator.